【正文】 各個動作的手動換向閥，習(xí)慣上稱為操縱閥。按壓力液通過操縱閥后的用途不同，可分為全流量操縱閥和先導(dǎo)液壓操縱閥。本章設(shè)計了整個支架的液壓系統(tǒng)，以保證液壓支架的正常工作。主要進行了各類閥體的選擇使用，以及立柱千斤頂?shù)牟季旨斑x型。第六章 結(jié)論放頂煤液壓支架是綜合機械化放頂煤開采最重要的機械設(shè)備。它的發(fā)明和應(yīng)用，使放頂煤開采技術(shù)從高落式進入一個全面機械化的新的發(fā)展階段。放頂煤工作面由液壓支架實現(xiàn)可靠、快速地支護和放煤，采用采煤機采煤，使厚煤層全厚開采在安全、可靠的工作條件下進行，保證了工作面實現(xiàn)高產(chǎn)高效。本論文在綜合分析國內(nèi)外放頂煤液壓支架的基礎(chǔ)之上，對液壓支架的工作原理及液壓支架的分類進行了概述，從而論證了放頂煤液壓支架的設(shè)計研究對于提高采煤工作面的綜合機械化水平具有重大意義。本課題在總結(jié)前人經(jīng)驗的基礎(chǔ)之上，主要完成了以下工作：（1）進行了液壓支架的整體結(jié)構(gòu)設(shè)計，主要包括支架主要尺寸的確定，頂梁、掩護梁結(jié)構(gòu)設(shè)計及參數(shù)確定，底座、立柱及液壓千斤頂?shù)倪x擇。其中重點進行了支架四連桿機構(gòu)的設(shè)計及計算，由此得到支架各部分的設(shè)計參數(shù)。（2）對支架重要部件進行了受力分析，主要包括頂梁、掩護梁及底座的受力分析，由于這些構(gòu)件在工況下的受力較為復(fù)雜，在對其受力分析時采用分離式的分析方法，這樣就簡化了分析過程，式分析過程更為清晰。（3）對液壓支架承載較大的構(gòu)件進行強度校核，包括頂梁強度校核，底座強度校核及前后連桿強度校核。在對其進行校核的過程中，通過Pro/E進行三維建模，然后得到其應(yīng)力應(yīng)變圖，使分析結(jié)果一目了然。（4）設(shè)計了整個支架的液壓系統(tǒng)，以保證液壓支架的正常工作。主要進行了各類閥體的選擇使用，以及立柱千斤頂?shù)牟季旨斑x型。參 考 文 獻[1] ：世界圖書出版社，1992[2] 邢福康，：煤炭工業(yè)出版社，1991[3] ：中國礦業(yè)學(xué)院出版社，1987[4] 楊振復(fù)，：煤炭工業(yè)出版社，1995[5]《綜采技術(shù)手冊》：煤炭工業(yè)出版社，2000[6] ：中國礦業(yè)大學(xué)出版社，2000[7] ：北京理工大學(xué)出版社，1998[8] ：化學(xué)工業(yè)出版社，2004[9] ：機械工業(yè)出版社，2003[10] Luciana D’Adderio．Crafting the virtual prototype：howfirms integrate knowledge and capabilities across organizational boundaries [J]．Elsevier Science，Research Policy，2001。30(9)：1409—1424．[11] 唐大放，：中國礦業(yè)大學(xué)出版社，2001[12] 張家鑒，. 北京：煤炭工業(yè)出版社，1985[13] ：上?？茖W(xué)技術(shù)出版社，2001[14] ：機械工業(yè)出版社，2003[15] ：高等教育出版社，1999[16] 中國機械工程學(xué)會、：江西科學(xué)技術(shù)出版社，2002[17] ：煤炭工業(yè)出版社,1999致謝這次畢業(yè)設(shè)計為我今后進入這一行業(yè)發(fā)展打下了扎實的基礎(chǔ)．總的來說,自己的確學(xué)了不少東西。首先，這是自己第一次的較大型的畢業(yè)設(shè)計，在老師的幫助和同學(xué)的合作下，學(xué)會了該怎樣作畢業(yè)設(shè)計，從哪兒下手，怎樣規(guī)劃，有了這次經(jīng)驗，下次會更加得心應(yīng)手．其次，自上大學(xué)以來，自己都學(xué)的是書本知識，而這次是理論聯(lián)系實踐，是自己更好的運用于掌握了這幾年說學(xué)的知識．再者，自己學(xué)會了該怎樣利用工具書和圖書館資源，知道如何找，上哪兒找，然后再加以吸收，補充自己的不足．最后，畢業(yè)設(shè)計培養(yǎng)了我嚴肅認真和實事求是的科學(xué)態(tài)度，從而培養(yǎng)了吃苦耐勞的精神和相對應(yīng)的工程知識。這次畢業(yè)設(shè)計，從開始分配任務(wù)到實習(xí)，查找資料到設(shè)計計算、制圖以及編寫說明書，自己都十分投入，從而保證了設(shè)計的質(zhì)量。在做設(shè)計的過程中，也有許多不足，有些學(xué)過的知識還不能夠和實際相聯(lián)系，很多東西不能學(xué)于至用；在參觀實習(xí)過程中，自己還不能把握住實習(xí)要點，希望老師能指點。這次畢業(yè)設(shè)計的圓滿完成還需感謝我的指導(dǎo)教師田和強老師的細心輔導(dǎo)，同時感謝曹連民老師、張鑫老師、張同軍老師等各位專業(yè)課老師的精心培養(yǎng)。由于此次本人的知識和技術(shù)有限，所以設(shè)計必不能盡善盡美，存在著的瑕疵未未還望老師批評指導(dǎo)。附錄 The designer aims to find the best design for the mechanical system considered. Part of this effort is the optimal choice of some selected parameters of a system.Fig. 1 Hydraulic supportMethods of mathematical programming can be used, if a suitable mathematical model of the system is made. Of course, it depends on the type of the system. With this formulation, good puter support is assured to look for optimal parameters of the system. The hydraulic support () described by Harl(1981) is a part of the mining industry equipment in the mine VelenjeSlovenia, used for protection of working environment in the gallery. It consists of two fourbar mechanismsFEDG and AEDB as show in . The mechanism AEDB defines the part of coupler point C and the mechanism FEDG is used to drive the support by a hydraulic is required that the motion the support ,more precisely, the motion of point C in , is vertical with minimal transversal displacements. If this is not the case, the hydraulic support will not work properly because it is stranded on removal of the earth machine. A prototype of the hydraulic support was tested in a laborarory (Grm 1992). The support exhibited large ransversal displacements, which would reduce its employability. Therefore, a redesign was necessary. The project should be improved with minimal cost if possible. It was decided to find the best values for the most problematic parameters a1,a2,a4 of the leading fourbar mechanism AEDB with methods of mathematical programming. Otherwise it would be necessary to change the project, at least mechanism AEDB. The solution of above problem will be different because of tolerances of varoious parameters of the system, whichis why the maximal allowed tolerances of parameters a1,a2,a4 will be calculate, with help of methods of mathematical programming. Two fourbar mechanisms deterministic model of the hydraulic supportAt first it is necessary to develop an appropriate mechanical model of the hydraulic support. It could be based on the following assumptions:the links are rigid bodies,the motion of individual links is relatively show.The hydraulic support is a mechanism with one degree of freedom. Its kinematics can be modeled with synchronous motion of two fourbar mechanisms FEDG and AEDB (Oblak et ). The leading fourbar mechanism AEDB has a decisive influence on the motion of the hydraulic support. Mechanism 2 is used to drive the support by a hydraulic actuator. The motion of the support is well described by the trajectory L of the coupler point C. Therefore, the task is to find the optimal values of link lengths of mechanism 1 by requiring that the trajectory of the point C is as possible to the desired trajectory K. The synthesis of the fourbar mechanism 1 has been performed with help of kinematics equations of motion given by Rao and Dukkipati(1989). The general situation is depicted in . Trajectory L of the point C . Trajectory L of the point CEquation of trajectory L of the point C will be written in the coordinate frame considered. Coordinate x and y of the point C will be written with the typical parameters of a fourbar mechanism a1a2…..a6. The coordinates of points B and D are =cos, (1)=sin (2) =cos(+) (3)=sin(+) (4)The parameters A1a2…..a6 are related to each other by+= (5)()+= (6)By substituting （1）—（4）into（5）—（6）the response of the support are obtained as(Xcos)+(Ysin)=0 (7)[Xcos(+)]+[Ysin(+)]=0 (8)This equation represents the base of the mathematical model fore calculating the optimal values of parameters a1,a2,a4. modelThe mathematical model of the system will be in the from proposed by Haug and Arora (1979):minf(u,v) （9）subject to constraints：（u,v）0,I=1,2……..,m. （10）and response equations:(u,v)=0,j=1,2,….,m. （11）The vect